It is generally known that this type of powder comprises a powdered base, selected in particular from the group including talc, rice starch, kaolin, silk powder or polymer powder, to which pigments are added to obtain a coloration, examples being the oxides of titanium, zinc or iron. If a pearly effect is desired, a mica powder or a powder of mica coated with metal oxides, in particular of titanium and bismuth, or aluminum powders is added. To obtain sufficient adherence to the skin, a small quantity of binder is typically added, for example vegetable, animal, mineral or synthetic oils, zinc stearate, sorbitol or lanolin. These powders may also contain preservatives such as methylparaben or propylparaben, surfactants (preferably nonionic), and fragrances.
To obtain a makeup compact, the fluid base powder is disposed on the bottom of a container, in which a piston or punch, which compresses the powder to assure the cohesion of its grains, is made to slide. In general, it is arranged that the container is defined at its bottom by a tray that receives the resulting compact product.
The goal of this compacting operation is to obtain the greatest possible cohesion of the grains of the base powder, to prevent the compact from crumbling; this result, which depends on the texture of the powder that is compacted, is not always easy to attain. Moreover, binders may be used in combination with the powder to modify the texture of the compact or to improve its cohesion; in that case, the binders must be distributed evenly and homogeneously throughout the product during compacting, which in practice is no always attained.